Updated: 13 October 2019
It’s a minefield trying to buy a sunscreen which doesn’t harm the sea life. Even those trumpeting their green credentials are not always free from harmful chemicals and components. You have to read the label very carefully. So what are the nasties of which scuba divers and snorkellers should be wary?
Nano particles are minute chemical substances, which are about 100,000 times smaller than the diameter of a human hair.
Titanium dioxide and zinc oxide nanoparticles are often used in sunscreens. They allow clear sunscreen which can be sprayed on. However, they produce significant amounts of hydrogen peroxide, a strong oxidizing agent that generates high levels of stress on reef-building corals and marine phytoplankton. They have also been shown to make sea urchin embryos more vulnerable to toxins.
You need to avoid nanoparticles if you are looking for a marine-friendly sunscreen.
Scientists have shown that Oxybenzone (also known as Benzophenone-2 or BP-2) increases the rate of coral bleaching. Additionally, the chemical damages the coral’s dna, affecting their reproduction. If that wasn’t enough other effects are to make juvenile corals become grossly deformed and encase themselves with their own skeletons.
Octinoxate, Butylparaben, 4-Methylbenzylidene Camphor
Another study, this time by Roberto Danovaro et al, named butylparaben, octinoxate and 4-methylbenzylidene camphor as being harmful to reefs.
Octocrylene, which is also in some hair sprays and conditioners, accumulates in coral as fatty acid esters that could be toxic to the marine organism according to research published in 2019.
How Much of a Problem is it?
According to NOAA (National Oceanic and Atmospheric Administration) 4,000 to 6,000 tons of sunscreen enters reef areas annually. This does not spread out rapidly or evenly over the entire ocean, but concentrates on popular tourist sites. It is estimated that 90% of snorkellers and scuba divers are found on just 10% of the world’s reefs
So which sunscreens can you use?
Look for ones without the ingredients mentioned above. Zinc oxide and Titanium dioxide are good as long as they are not in nano-format. A quick guide is whether the sunscreen is clear or not. If it is clear, or in a spray, it probably contains nano-particles.
If the ingredients state “uncoated” zinc oxide then these are larger particles (non-nano).
According to a report published by Wageningen Marine Research, the best sunscreens for the environment are those using titanium as the active ingredient.
Any others you’d recommend – let us know in the comments below.
References and Further Reading
Sunscreen nanoparticles harm sealife. SCUBA News 2015.
Downs, C.A., Kramarsky-Winter, E., Segal, R. et al. Arch Environ Contam Toxicol (2016) 70: 265. doi:10.1007/s00244-015-0227-7
Danovaro, Roberto; Bongiorni, Lucia; Corinaldesi, Cinzia; Giovannelli, Donato; Damiani, Elisabetta; et al. Environmental Health Perspectives; Research Triangle Park116.4 (Apr 2008): 441-7.
The impacts of sunscreen on coral reefs. National Park Service.
DME Slijkerman and M Keur. Sunscreen ecoproducts – Product claims, potential effects and environmental risks of applied UV filters, Wageningen Marine Research 2018.
Sunscreen and cosmetics compound may harm coral by altering fatty acids, American Chemistry Society 2019